I think this makes perfect sense if you think about it. We are great at pattern recognition and separating things into categories. If say 90% of your average daily interaction is one race, including people you see every day (classmates, workmates, etc) one has to be able to discern all the more subtle differences between people vs the more obvious and unique outliers.
If I were doing a study on this, I’d test say black kids at predominately white schools, and white kids at predominately black schools, and I bet both would test out better than the average. Due to their exposure, they will have a lot more instances where they will be able to discern more subtle differences between people.
